Communication method and device

Abstract

This application discloses a communication method and apparatus. A switch device or radio frequency device in a fronthaul network monitors clock offset information between first time information and second time information, where the first time information is time information synchronized via a fronthaul interface corresponding to a first baseband unit, and the second time information is time information synchronized via a fronthaul interface corresponding to a second baseband unit. The clock offset information is used to assist in fault handling of the baseband units, thereby reducing operation and maintenance costs and improving fault handling efficiency.

Description

Technical Field

[0001] This application relates to the field of communication technologies, and in particular, to communication methods and apparatuses.

Background Art

[0002] In a distributed base station architecture, one radio frequency device can establish communication connections to a plurality of baseband units (BBUs), but the radio frequency device maintains time synchronization with only one of the plurality of BBUs. When the times of the plurality of BBUs are not synchronized, signal interference is generated in the communication between the radio frequency device and the plurality of BBUs, and abnormal communication services may occur.

[0003] Currently, when an abnormality occurs in the communication service of a distributed base station, an operator needs to carry a test device and individually check the times of different BBUs on site to perform fault handling. Since this approach depends on manual operations and test equipment, the operation and maintenance costs are high, the fault handling time is long, and the efficiency is low.

Summary of the Invention

[0004] This application provides a communication method and apparatus for reducing the operation and maintenance costs corresponding to BBUs in a fronthaul network and improving the fault handling efficiency.

[0005] According to a first aspect, an embodiment of this application provides a communication method. The method may include a first device obtaining first time information and second time information and transmitting clock offset information. The clock offset information indicates an offset between the first time information and the second time information, the first time information is time information synchronized via a fronthaul interface corresponding to a first baseband unit, and the second time information is time information synchronized via a fronthaul interface corresponding to a second baseband unit.

[0006] In the aforementioned design, when multiple BBUs access the same fronthaul network, a clock offset is determined between time information synchronized via clock sources of different BBUs. Fault handling is performed on the relevant BBU based on the clock offset. Since there is no need to manually carry test devices, operational and maintenance costs can be reduced and fault handling efficiency can be improved.

[0007] In a possible design, before transmitting clock offset information, the first device may further determine, based on first and second time information, that the first baseband unit is the master clock device. Optionally, the master clock device may be referred to as the primary BBU.

[0008] In possible designs, the second baseband unit may be a non-master clock device (or non-primary BBU), or it may be one of several non-master clock devices. In this design, the clock offset between one or more non-primary BBUs and the primary BBU can be monitored.

[0009] In a possible design, the first device may transmit clock offset information to a second device, which may be used for fault detection of the second baseband unit. The second device may be a second baseband unit or a network management device, allowing for flexible fault handling for the baseband unit by using different devices.

[0010] In a possible design, the first device may further transmit first information to the first baseband unit, which may indicate one or more of the following: that the first baseband unit is a master clock device, and that the clock offset between the first baseband unit and the master clock device is zero. Based on such a design, the first baseband unit may determine that it is a master clock device.

[0011] In a possible design, the first device could be a radio frequency device or a switch device in a fronthaul network, and the radio frequency device communicates with a first baseband unit and a second baseband unit.

[0012] In a possible design, if the first device is a switch device in a fronthaul network, the switch device may further provide a clock source to the radio frequency device based on first time information, and the radio frequency device communicates with a first baseband unit and a second baseband unit. Such a design can implement synchronization between the radio frequency device and the first baseband unit.

[0013] In possible designs, a first baseband unit is time-synchronized with a first external clock reference source, and a second baseband unit is time-synchronized with a second external clock reference source, and the first and second external clock reference sources may be the same or different. In other words, the method provided in this embodiment of the present application may be applied to scenarios in which the baseband units are not synchronized because the external clock reference sources are not synchronized, and may also be applied to scenarios in which the baseband units are not synchronized because the external clock reference sources are the same but jumps occur.

[0014] According to a second aspect, an embodiment of the present application provides a communication method in which a second device receives clock offset information, the clock offset information indicating an offset between first time information and second time information, the first time information being time information synchronized via a fronthaul interface corresponding to a first baseband unit, and the second time information being time information synchronized via a fronthaul interface corresponding to a second baseband unit, and the second device may determine, based on the clock offset information, whether a fault exists in the second baseband unit.

[0015] In a possible design, the second device could be a radio frequency device or a switching device within a fronthaul network.

[0016] In a possible design, the first baseband unit may be the master clock device (or primary BBU).

[0017] In possible designs, the second baseband unit may be a non-master clock device (or non-primary BBU), or the second baseband unit may be any one of several non-master clock devices.

[0018] In a possible design, the first baseband unit is time-synchronized with a first external clock reference source, and the second baseband unit is time-synchronized with a second external clock reference source, and the first and second external clock reference sources may be the same or different.

[0019] According to a third aspect, embodiments of the present application provide a communication device. The communication device may be a first device, or a device, module, chip, etc., within the first device, or a device that can be used in matching with the first device. In design, the communication device may include modules that correspond one-to-one with the methods / operations / steps / actions described in the first aspect. Modules may be implemented by hardware circuitry, software, or a combination of hardware circuitry and software. In design, the communication device may include a processing module and a communication module.

[0020] The communication module is configured to acquire first time information and second time information, the first time information being time information synchronized via a fronthaul interface corresponding to a first baseband unit, the second time information being time information synchronized via a fronthaul interface corresponding to a second baseband unit, and to transmit clock offset information, the clock offset information indicating the offset between the first time information and the second time information.

[0021] The processing module is configured to control the communication module to perform acquisition or transmission operations.

[0022] In a possible design, the processing module is further configured to determine, based on first and second time information, that the first baseband unit is the master clock device. Optionally, the master clock device may be referred to as the primary BBU.

[0023] In possible designs, the second baseband unit may be a non-master clock device (or non-primary BBU), or the second baseband unit may be any one of several non-master clock devices.

[0024] In a possible design, the communication module may be configured to send clock offset information to a second device, and the clock offset information is used for fault determination of the second baseband unit. The second device may be the second baseband unit or a network management device.

[0025] In a possible design, the communication module may be further configured to send first information to the first baseband unit, and the first information indicates one or more of that the first baseband unit is a master clock device and that the clock offset between the first baseband unit and the master clock device is zero. Based on such a design, the first baseband unit may determine that the first baseband unit is a master clock device.

[0026] In a possible design, the first device may be a radio frequency device or a switch device in a front haul network, and the radio frequency device communicates with the first baseband unit and the second baseband unit.

[0027] In a possible design, when the first device is a switch device in a front haul network, the processing module is further configured to provide a clock source to the radio frequency device based on the first time information, and the radio frequency device communicates with the first baseband unit and the second baseband unit.

[0028] In a possible design, the first baseband unit is time synchronized with a first external clock reference source, the second baseband unit is time synchronized with a second external clock reference source, and the first external clock reference source and the second external clock reference source are the same or different.

[0029] According to the fourth aspect, embodiments of the present application provide a communication device. The communication device may be a second device, or a device, module, chip, etc. within the second device, or a device that can be used in matching with the second device. In design, the communication device may include modules that correspond one-to-one with the methods / operations / steps / actions described in the second aspect. The modules may be implemented by a hardware circuit, software, or a combination of a hardware circuit and software. In design, the communication device may include a processing module and a communication module.

[0030] The communication module is configured to receive clock offset information, where the clock offset information indicates an offset between first time information and second time information. The first time information is time information synchronized via a fronthaul interface corresponding to a first baseband unit, and the second time information is time information synchronized via a fronthaul interface corresponding to a second baseband unit. The processing module is configured to determine whether there is a failure in the second baseband unit based on the clock offset information.

[0031] In a possible design, the second device may be a radio frequency device or a switch device in a fronthaul network.

[0032] In a possible design, the first baseband unit may be a master clock device (or called a primary BBU).

[0033] In a possible design, the second baseband unit may be a non-master clock device (or called a non-primary BBU), or the second baseband unit may be any one of a plurality of non-master clock devices. <统一格式,将 改为

[0034] In a possible design, the first baseband unit is time-synchronized with a first external clock reference source, and the second baseband unit is time-synchronized with a second external clock reference source, and the first and second external clock reference sources may be the same or different.

[0035] According to a fifth aspect, embodiments of the present application provide a communication device. The communication device may include a processor configured to carry out the method described in the first aspect. The processor is coupled to memory, the memory is configured to store instructions and data, and the method described in the first aspect can be carried out when the processor executes instructions stored in memory. Optionally, the communication device may further include memory. The communication device may further include a communication interface, which is used by the device to communicate with another device. For example, the communication interface may be a transceiver, a circuit, a bus, a module, a pin, or another type of communication interface.

[0036] The communication interface is configured to acquire first time information and second time information, the first time information being time information synchronized via a fronthaul interface corresponding to a first baseband unit, the second time information being time information synchronized via a fronthaul interface corresponding to a second baseband unit, and to transmit clock offset information, the clock offset information indicating the offset between the first time information and the second time information.

[0037] The processor is configured to control the communication interface and perform acquisition or transmission operations.

[0038] According to a sixth aspect, embodiments of the present application provide a communication device. The communication device may include a processor configured to carry out the method described in a second aspect. The processor is coupled to memory. The memory is configured to store instructions and data. The method according to the second aspect can be carried out when the processor executes instructions stored in memory. Optionally, the communication device may further include memory. The communication device may further include a communication interface, which is used by the device to communicate with another device. For example, the communication interface may be a transceiver, a circuit, a bus, a module, a pin, or another type of communication interface.

[0039] The communication interface is configured to receive clock offset information, which indicates an offset between first time information and second time information, where the first time information is time information synchronized via a fronthaul interface corresponding to a first baseband unit, and the second time information is time information synchronized via a fronthaul interface corresponding to a second baseband unit, and the processor is configured to determine, based on the clock offset information, whether a failure exists in the second baseband unit.

[0040] According to the seventh aspect, an embodiment of the present application provides a communication system including a communication device according to the third or fifth aspect and a communication device according to the fourth or sixth aspect.

[0041] According to the eighth aspect, embodiments of the present application further provide a computer program. When the computer program is executed on a computer, the computer can perform the method according to the first or second aspect.

[0042] According to the ninth aspect, embodiments of the present application further provide a computer program product including instructions. When the instructions are executed on a computer, the computer can perform the method according to the first or second aspect.

[0043] According to the tenth aspect, embodiments of the present application further provide a computer-readable storage medium. The computer-readable storage medium stores a computer program or instruction. When the computer program or instruction is executed on a computer, the computer can perform the method according to the first or second aspect.

[0044] According to the eleventh aspect, embodiments of the present application further provide a chip configured to read a computer program stored in memory and to perform a method according to the first or second aspect, or the chip includes a circuit configured to perform a method according to the first or second aspect.

[0045] According to a twelfth aspect, embodiments of the present application further provide a chip system. The chip system includes a processor configured to support an apparatus carrying out the method according to the first or second aspect. In a possible design, the chip system further includes memory, which is configured to store programs and data required by the apparatus. The chip system may include a chip, or a chip and other separate components.

[0046] For the effects of the solutions provided in any one of the second through twelfth embodiments, please refer to the corresponding description in the first embodiment. [Brief explanation of the drawing]

[0047] [Figure 1] This is a diagram illustrating the structure of a communication system. [Figure 2A] This is a diagram of a wireless access network (RAN). [Figure 2B]This is a diagram of a functional module for an access network device. [Figure 2C] This is a diagram illustrating the division of the physical layer into functional modules. [Figure 2D] This is another diagram showing the division of the physical layer into functional modules. [Figure 3] This is a structural diagram of the fronthaul network. [Figure 4A] This is a diagram illustrating the structure of a distributed base station. [Figure 4B] This is a diagram illustrating the structure of a distributed base station. [Figure 5A] This is a diagram illustrating the structure of a distributed base station. [Figure 5B] This is a structural diagram of a distributed base station. [Figure 5C] This is a diagram illustrating the structure of a distributed base station. [Figure 6] This is a schematic flowchart of the communication method. [Figure 7] This is a schematic flowchart of the communication method. [Figure 8] This is a structural diagram of a communication device. [Figure 9A] This is a diagram illustrating the structure of a distributed base station. [Figure 9B] This is a diagram illustrating the structure of a distributed base station. [Figure 10] This is a structural diagram of another communication device. [Modes for carrying out the invention]

[0048] To further clarify the purpose, technical solutions, and advantages of the embodiments of this application, the embodiments of this application will be described in more detail below with reference to the accompanying drawings.

[0049] In embodiments of this application, at least one (item) refers to one or more (items). "Multiple (items)" means two (items) or more than two (items). The term "and / or" describes a relational relationship for describing related objects and indicates that three relationships may exist. For example, A and / or B may represent the following three cases: only A exists, both A and B exist, and only B exists. The letter " / " usually indicates an "or" relationship between related objects. In addition, terms such as "first" and "second" may be used in embodiments of this application to describe objects, but it should be understood that these objects should not be limited by these terms. These terms are simply used to distinguish objects from one another.

[0050] In the following description of embodiments of this application, the terms “includes,” “has,” and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device comprising a set of steps or units may, at their discretion, further include other steps or units not listed, or further include other specific steps or units of the process, method, product, or device, at their discretion. Note that in embodiments of this application, the words “exemplary” or “for example” are used to indicate an example, illustration, or description. Any method or design solution described as “example” or “for example” in embodiments of this application should not be described as being more preferable or having more advantages than another method or design solution. More precisely, the use of words such as “example” or “for example” is intended to present a concept relative in a particular way.

[0051] The technology provided in the embodiments of this application can be applied to various communication systems. Figure 1 is a diagram of a possible and non-limiting communication system. As shown in Figure 1, the communication system 1000 includes a radio access network (RAN) 100 and a core network (CN) 200. The RAN 100 includes at least one RAN node (e.g., 110a and 110b in Figure 1, collectively referred to as 110) and at least one terminal (e.g., 120a to 120j in Figure 1, collectively referred to as 120). The RAN 100 may also include another RAN node, e.g., a radio relay device and / or a radio backhaul device (not shown in Figure 1). The terminal 120 is connected to the RAN node 110 wirelessly. The RAN node 110 is connected to the core network 200 wirelessly or wired. The RAN node 110 is configured to help the terminal perform radio access. The core network devices in the core network 200 and the RAN node 110 in the RAN 100 may be different physical devices, or they may be the same physical device integrating the logical functions of the core network and the wireless access network. Optionally, the RAN node 110 may be further connected to the Internet 300, or may be connected to the Internet 300 by using the core network 200.

[0052] RAN100 is a third-generation partnership project (3 rd Generation Partnership Project (3GPP), for example, the 4th generation (4 th generation (4G) or 5th generation (5 thRAN100 may be a cellular system related to a 5G mobile communication system or a future-oriented advanced system (e.g., a 6G mobile communication system). Alternatively, RAN100 may be an OpenRAN (O-RAN, or ORAN) or a Cloud Radio Access Network (CRAN). Alternatively, RAN100 may be a communication system that integrates two or more of the aforementioned systems. A 4G mobile communication system includes a Long Term Evolution (LTE) system, and a 5G mobile communication system includes a New Radio (NR) system.

[0053] Multiple RAN nodes 110 within the communication system 1000 may be nodes of the same category or nodes of different categories. In some scenarios, the roles of the RAN nodes 110 and terminals 120 are relative to each other. For example, network element 120i in Figure 1 may be a helicopter or unmanned aerial vehicle and may be configured as a mobile base station. For terminal 120j accessing RAN 100 using network element 120i, network element 120i is a base station. However, for base station 110a, network element 120i is a terminal. Both RAN nodes 110 and terminals 120 may be referred to as communication devices. For example, network elements 110a and 110b in Figure 1 may be understood as communication devices with base station functionality, and network elements 120a to 120j may be understood as communication devices with terminal functionality.

[0054] The terminals and RAN nodes are described in detail below.

[0055] (1) Terminal

[0056] Alternatively, a terminal may be referred to as a terminal device, user equipment (UE), mobile station, or mobile terminal. A terminal may be a user-side entity configured to receive or transmit signals. A terminal may communicate with one or more core networks by using a RAN. Terminals include handheld devices with wireless connectivity, other processing devices connected to a wireless modem, and in-vehicle devices. Communication devices may be portable, pocket-sized, handheld, computer-integrated, or vehicle-mounted mobile devices. The terminal can be broadly applied to various scenarios such as cellular communication, device-to-device (D2D), vehicle-to-everything (V2X) communication, end-to-end P2P, machine-to-machine (M2M), machine-type communication (MTC), Internet of Things (IoT), virtual reality (VR), augmented reality (AR), industrial control, autonomous driving, telemedicine, smart grids, smart furniture, smart offices, smart wearables, smart transportation, smart cities, mobile phones, tablet computers, computers with wireless transceiver capabilities, wearable devices, vehicles, unmanned aerial vehicles, helicopters, aircraft, ships, robots, robotic arms, and smart home devices. The device form of the terminal is not limited to the embodiments of this application.

[0057] (2) RAN node

[0058] In possible scenarios, a RAN node may be alternatively called an access network device, RAN entity, access node, network device, etc., and may form part of a communication system to help terminals perform wireless access. A RAN node is a base station (BS), evolved base station (eNB), access point (AP), transmission reception point (TRP), next generation NodeB (gNB), sixth generation (6 th RAN nodes can be next-generation base stations in 6G mobile communication systems, or base stations in future mobile communication systems. RAN nodes can be macro base stations (e.g., 110a in Figure 1), micro base stations or indoor stations (e.g., 110b in Figure 1), relay nodes or donor nodes, or radio controllers in CRAN scenarios. Optionally, RAN nodes can also be servers, wearable devices, vehicles, or in-vehicle devices. For example, access network devices for vehicle-to-everything (V2X) technology can be roadside units (RSUs).

[0059] In another possible scenario, multiple RAN nodes work together to help terminals perform radio access, while different RAN nodes perform several functions of the access network device separately. Figure 2A is a diagram of a radio access network RAN. As shown in Figure 2A, the access network device includes a central unit (CU), a distributed unit (DU), and a radio unit (RU). The CU may be connected to the core network and one or more DUs. One DU may be connected to one or more RUs, and the interface between the DU and the RU may be called a fronthaul interface (FH). Optionally, the CU may have several functions of the core network, and the CU includes a CU control plane (CP) and a CU user plane (UP). The RU is configured to transmit signals to terminals or receive signals from terminals. For example, a RAN node could be a CU, DU, CU-CP, CU-UP, or RU.

[0060] In different systems, CU (or CU-CP and CU-UP), DU, or RU may have alternative names, but it can be understood that those skilled in the art will be able to understand the meaning of the names. For example, in an ORAN system, CU may be alternatively called O-CU (open CU), DU may be alternatively called O-DU, CU-CP may be alternatively called O-CU-CP, CU-UP may be alternatively called O-CU-UP, and RU may be alternatively called O-RU. For the sake of clarity, CU, CU-CP, CU-UP, DU, and RU are used as illustrative examples in this application. Any one of CU (or CU-CP or CU-UP), DU, and RU in this application may be implemented using a software module, a hardware module, or a combination of a software module and a hardware module.

[0061] (3) Disassembly of access network devices into power modules

[0062] Communication between access network devices and terminals conforms to a specific protocol layer structure. The protocol layers may include a control plane protocol layer and a user plane protocol layer. For example, the control plane protocol layer may include at least one of the following: radio resource control (RRC) layer, packet data convergence protocol (PDCP) layer, radio link control (RLC) layer, media access control (MAC) layer, and physical (PHY) layer. The user plane protocol layer may include at least one of the following: service data adaptation protocol (SDAP) layer, PDCP layer, RLC layer, MAC layer, and physical layer. CUs and DUs may be configured based on the protocol layer functions of the radio network they perform. For example, a CU may be configured to perform the functions of the PDCP layer and higher protocol layers (e.g., the RRC layer and / or the SDAP layer), and a DU may be configured to perform the functions of protocol layers below the PDCP layer (e.g., the RLC layer, MAC layer, and / or the PHY layer). In another example, the CU is configured to perform the functions of the protocol layer above the PDCP layer (e.g., the RRC layer and / or the SDAP layer), and the DU is configured to perform the functions of the PDCP layer and the lower protocol layers (e.g., the RLC layer, MAC layer, and / or the PHY layer).

[0063] If the CU includes a CU-CP and a CU-UP, the CU-CP is configured to perform the control plane functions of the CU, and the CU-UP is configured to perform the user plane functions of the CU. For example, if the CU is configured to perform the functions of the PDCP layer, RRC layer, and SDAP layer, the CU-CP is configured to perform the functions of the RRC layer and the control plane functions of the PDCP layer, and the CU-UP is configured to perform the functions of the SDAP layer and the user plane functions of the PDCP layer.

[0064] The above configurations of CUs or DUs are merely examples, and the functionality of a CU or DU can alternatively be configured based on requirements. For example, a CU or DU may be configured to have more protocol layer functionality, or it may be configured to have some of the protocol layer processing functionality. For example, some RLC layer functionality and protocol layer functionality above the RLC layer may be placed on the CU, while the remaining RLC layer functionality and protocol layer functionality below the RLC layer may be placed on the DU. In another example, the division of functionality into CUs or DUs may be based on service type or other system requirements. For example, the division may be based on latency. Functionality that needs to meet low latency requirements may be placed on the DU, while functionality that does not need to meet latency requirements may be placed on the CU.

[0065] Optionally, the DU and RU may cooperate to jointly perform functions of the PHY layer. As shown in Figure 2B, the access network device includes one or more functional modules configured to perform signal processing. Using physical layer functions as an example, the access network device includes one or more functional modules from coding, rate matching, scrambling, modulation, layer mapping, precoding, resource element (RE) mapping, digital beamforming (BF), inverse fast fourier transform (IFFT) / cyclic prefix (CP) addition, decoding, derate matching, descrambling, demodulation, inverse discrete fourier transform (IDFT), channel equalization (or channel estimation), RE demapping, digital BF, and fast fourier transform (FFT) / CP rejection, digital to analog (DA) conversion, analog BF, analog to digital (AD) conversion, or analog BF.

[0066] One or more functional modules may be implemented using software, hardware, or a combination of software and hardware. Physically, functional modules may be separate or integrated. It should be understood that the functional modules described above are merely examples. Depending on the design, an access network device may include more other modules (e.g., scheduling modules, power control modules, hybrid automatic repeat request (HARQ) modules, flow control modules, mobility management modules, or artificial intelligence (AI) modules) or may not include the functional modules shown in Figure 2B (e.g., not including the digital BF module).

[0067] The functions of DU and RU can be configured in multiple ways based on the design.

[0068] For example, the DU may be configured to perform baseband functions, and the RU may be configured to perform intermediate radio frequency functions. In another example, the DU may be configured to perform higher-layer functions of the PHY layer, and the RU may be configured to perform lower-layer functions of the PHY layer, or lower-layer functions and radio frequency functions. Higher-layer functions of the physical layer may include some of the physical layer functions, and this part of the functions is closer to the MAC layer. Lower-layer functions of the physical layer may include other parts of the physical layer functions, and this part of the functions is closer to the intermediate radio frequency side.

[0069] A front-haul interface exists between the DU and RU. For example, the communication protocol for the front-haul interface may be the Common Public Radio Interface (CPRI) interface protocol, the Enhanced Common Public Radio Interface (eCPRI) interface protocol, etc. This is not limited to these. Different front-haul interfaces correspond to DUs and RUs with different functions.

[0070] As shown in Figure 2C, when the fronthaul interface between the DU and RU is CPRI, the PHY functions shown in Figure 2B are divided into baseband functions and radio frequency functions. The DU is configured to perform one or more of the baseband functions, and the RU is configured to perform one or more of the radio frequency functions.

[0071] As shown in Figure 2D, when the fronthaul interface between the DU and RU is eCPRI, compared to CPRI, some downlink and / or uplink baseband functions are moved from the DU to the RU for implementation. Different division schemes between the DU and RU correspond to different categories (category, abbreviated as Cat) of eCPRI. Figure 2D provides six examples of eCPRI represented by Cat A, B, C, D, E, and F (alternatively, they may be represented as options A-F, options 1-6, or other schemes). It can be understood that there may be other division schemes between the DU and RU, i.e., there may be other categories of eCPRI.

[0072] Using eCPRICatA as an example, in downlink transmission, layer mapping is used as decomposition. The DU is configured to perform layer mapping and one or more previous functions (i.e., one or more of coding, rate matching, scrambling, modulation, and layer mapping), as well as another function after layer mapping has been moved to the RU for implementation (e.g., RE mapping, digital BF, or IFFT / CP addition). In uplink transmission, RE demapping is used as decomposition. The DU is configured to perform demapping and one or more previous functions (i.e., one or more of decoding, rate matching, descrambling, demodulation, IDFT, channel equalization, and RE demapping), as well as another function after demapping has been moved to the RU for implementation (e.g., one or more of digital BF or FFT / CP rejection).

[0073] Similarly, eCPRICatB, CatC, CatD, CatE, and CatF correspond to different division schemes between the DU and RU. Functions at and before the division point are performed by the DU, and functions after the division point are performed by the RU. For the division points of various types of eCPRIC, refer to Figure 2D, and the details will not be described one by one. For example, in eCPRICatB, RE mapping is used as a division for downlink transmission, and RE demapping is used as a division for uplink transmission. In uplink transmission, RE mapping and functions before RE mapping are performed by the DU, and functions after RE mapping and radio frequency functions are performed by the RU. In downlink transmission, RE demapping and functions before RE demapping are performed by the DU, and functions after RE demapping and radio frequency functions are performed by the RU.

[0074] The division scheme of eCPRI may be symmetric with respect to the uplink and downlink, for example, eCPRICatB and CatC shown in Figure 2D, or it may be asymmetric with respect to the uplink and downlink, for example, eCPRICatA, CatD, CatE, and CatF shown in Figure 2D. However, at an optional but not limited choice, different division schemes may be configured for different channels or different channel groups in the uplink and / or downlink, i.e., different categories of eCPRI may be configured. One group of channels may contain one or more channels.

[0075] In possible implementations, CUs and DUs are contained within the same network element, e.g., a baseband unit (BBU). RUs may be contained within a radio frequency device (or radio frequency unit), e.g., a radio frequency device may be a remote radio unit (RRU), an active antenna unit (AAU), or a remote radio head (RRH). A processing unit within a BBU configured to perform baseband functions is called a baseband high (BBH) unit, and a processing unit within an RRU / AAU / RRH configured to perform baseband functions is called a baseband low (BBL) unit.

[0076] The BBU and radio frequency devices may be integrated into a single cabinet, or they may be separated. For example, the BBU may be housed in a cabinet, and the radio frequency devices may be deployed at remote ends where signal coverage is required. An access network device in which the BBU and radio frequency devices are separated may be understood as a distributed access network device, or may be called a distributed base station.

[0077] The interface between the BBU and the radio frequency device may alternatively be called a fronthaul interface. To implement a fronthaul interface, the DU and RU may be connected using a fronthaul network, or the BBU and radio frequency device may be connected using a fronthaul network. For example, a fronthaul network includes, but is not limited to, fiber direct connection and wavelength division network. From the perspective of radio frequency devices, the BBU may alternatively be described as a radio frequency control device. One end of the fronthaul interface is a radio frequency control device, and the other end is a radio frequency device. Alternatively, the radio frequency control device and the radio frequency device may be named according to the communication protocol of the fronthaul interface. For example, as shown in Figure 3, if the communication protocol of the fronthaul interface is the eCPRI protocol, the radio frequency control device may be eCPRI radio equipment control (eREC), and the radio frequency device may be eCPRI radio equipment (eRE). As another example, in an ORAN system, the radio frequency control device may be a DU, CU, or BBU, and the radio frequency device may be a RU, RRU, AAU, or RRH. In this embodiment of the present application, the BBU and radio frequency device are used as illustrative examples.

[0078] In a distributed base station, one BBU may be connected to multiple radio frequency devices, and the fronthaul interfaces between different radio frequency devices and the BBU may correspond to different transmission paths. In an optional implementation, the BBU may be directly connected to at least one of the multiple radio frequency devices by using a transmission medium such as optical fiber (fiber optic cable) or electrical cable. As shown in Figure 4A, a distributed base station includes one BBU and two radio frequency devices, namely a first radio frequency device and a second radio frequency device. The BBU and the two radio frequency devices may be connected by using different optical fibers. In another optional embodiment, the BBU and radio frequency devices may, alternatively, be connected to each other by using a fronthaul network that includes one or more switch devices. Such a fronthaul network may, alternatively, be called fronthaul networking. A single radio frequency device may be connected to the BBU by using a one-hop switch device or a multi-hop switch device. The switch devices connected between different radio frequency devices and the BBU may be the same or different. For example, as shown in Figure 4B, a distributed base station includes one BBU and two radio frequency devices, namely a first radio frequency device and a second radio frequency device. The BBU is connected to a switch device in the fronthaul network using optical fiber, and the two radio frequency devices are connected to a switch device in the fronthaul network using optical fiber.

[0079] Based on requirements such as resource redundancy and reliability, multiple BBUs may sometimes access the same fronthaul network. In other words, one radio frequency device may be connected to multiple BBUs. For example, Figure 5A shows a distributed base station with one radio frequency device and two BBUs, specifically BBU1 and BBU2. The radio frequency device may be connected to the two BBUs by using different optical fibers. For example, Figure 5B shows another distributed base station with BBU1, BBU2, and a radio frequency device. BBU1 and BBU2 access a fronthaul network that includes a switch device, and radio frequency device 1 and radio frequency device 2 also access the fronthaul network. In another example, Figure 5C shows yet another distributed base station with BBU1, BBU2, radio frequency device 1, and radio frequency device 2. BBU1 and BBU2 access a fronthaul network that includes a switch device, and radio frequency device 1 and radio frequency device 2 also access the fronthaul network. The fronthaul network includes switch devices 1, 2, 3, and 4. BBU1 is indirectly connected to switch device 3 using switch device 1, BBU2 is indirectly connected to switch device 3 using switch device 2, radio frequency device 1 is indirectly connected to switch device 3 using switch device 4, and radio frequency device 2 is directly connected to switch device 3.

[0080] In addition, Figures 4A, 4B, 5A, 5B, and 5C further show that the BBU may be connected to a network management device, and the interface between the network management device and the BBU may be referred to as the backhaul interface. Optionally, the fronthaul networks shown in Figures 4B, 5B, and 5C may be further connected to additional network management devices, which may manage the switch devices within the fronthaul network. For differentiation, in Figures 4B, 5B, and 5C, the network management device connected to the BBU using the backhaul interface is shown as network management device 1, and the additional network management device connected to the fronthaul network is shown as network management device 2.

[0081] A BBU provides a clock source to multiple connected radio frequency devices via a fronthaul interface. The radio frequency devices maintain clock or time synchronization with the BBU. Clock synchronization, also called frequency synchronization, means maintaining a specific relationship between the frequency or phase of a signal. For example, a signal may appear at the same average rate in its corresponding effective moment or effective time period, ensuring that all devices in the communication network operate at the same rate. For example, a radio frequency device maintaining clock synchronization with the BBU can be understood as the radio frequency device's local clock tracing the clock source (i.e., the BBU's clock) to achieve frequency synchronization, and the transmission / reception of the radio frequency device and the BBU's clock being synchronized. Time synchronization, also called phase synchronization, means that the frequency and phase of a signal match. For example, a radio frequency device maintaining time synchronization with the BBU can be understood as the radio frequency device's local clock tracing the clock source (i.e., the BBU's clock) to achieve phase synchronization.

[0082] When multiple BBUs are connected to the same fronthaul network, radio frequency devices maintain time synchronization with one of the BBUs. As shown in Figure 5A, a radio frequency device may select either clock source 1 provided by BBU1 or clock source 2 provided by BBU2 to perform time synchronization. As shown in Figure 5B, a switch device in the fronthaul network may select the same clock source (e.g., BBU1) provided by the same BBU to perform time synchronization for all radio frequency devices connected to the fronthaul network, or the switch device in the fronthaul network may select clock source 1 provided by BBU1 to perform time synchronization for radio frequency device 1, and clock source 2 provided by BBU2 to perform time synchronization for radio frequency device 2. As shown in Figure 5C, switch device 3 in the fronthaul network may select a clock source provided by the same BBU (e.g., BBU1) to perform time synchronization for all radio frequency devices connected to the fronthaul network, or switch device 3 in the fronthaul network may select clock source 1 provided by BBU1 to perform time synchronization for radio frequency device 1, and clock source 2 provided by BBU2 to perform time synchronization for radio frequency device 2.

[0083] It may be understood that two BBUs are shown as examples in Figures 5A, 5B, and 5C. The multiple BBUs in this embodiment of the present application may alternatively include more than two BBUs. For example, two BBUs are shown as examples in Figures 5A, 5B, and 5C. The multiple BBUs in this embodiment of the present application may alternatively include more than two BBUs. For example, two BBUs are shown as examples in Figures 5A, 5B, and 5C. The multiple BBUs in this embodiment of the present application may alternatively include more than two BBUs. For example, Figure 5A may further include BBU3, BBU4, ..., in addition to BBU1 and BBU2. This is not limited to the embodiments of the present application.

[0084] Generally, after clock source 1 and clock source 2 are synchronized using an external clock reference source, clock source 1 and clock source 2 are also time-synchronized, or BBU1 and BBU2 are time-synchronized, and the synchronization accuracy required by the service can be achieved. For example, synchronization between clock source 1 and clock source 2 can be achieved if the difference between each of their reference times is within an expected indicator (e.g., ±1100 ns). The reference time may be Coordinated Universal Time (UTC). In this case, the latency obtained based on their respective local times for data transmission between the BBUs where clock sources 1 / 2 are located and the corresponding radio frequency devices can satisfy the latency requirements required by the service.

[0085] However, because clock source 1 and clock source 2 are not the same clock source, an anomaly can occur where the clock offset exceeds the expected indicator. For example, a jump occurs in the external clock reference source corresponding to clock source 2, and as a result, the difference between clock source 2 and the reference time (e.g., 100ms) exceeds the expected indicator. In other words, clock source 1 and clock source 2 are not time-synchronized, or BBU1 and BBU2 are not time-synchronized. In this case, when radio frequency device 1, which maintains time synchronization with BBU1, communicates with BBU2, the communication latency has an offset because radio frequency device 1 and BBU2 are not time-synchronized, and the latency requirements demanded by the service cannot be met. As a result, the service is abnormal.

[0086] Currently, in response to the above service anomalies, operators need to bring test devices such as time test equipment or sweep generators to the site to detect the clock source of each BBU. If the difference between the BBU's clock source and a reference time is determined to exceed a expected indicator, the BBU's clock source may be determined to be abnormal. Furthermore, the BBU may be disconnected from the radio frequency device, fault handling may be performed on the BBU, and as a result, after the difference between the BBU's clock source and the reference time meets the expected indicator, the BBU is reconnected to the network and the associated service is restored. Such a design relies on manual operation and test devices, resulting in high operational and maintenance costs, long fault handling times, and low efficiency.

[0087] Based on this, embodiments of the present application provide a communication method. When multiple BBUs access the same fronthaul network, radio frequency devices or switch devices within the fronthaul network can determine the clock offset between the clock sources of different BBUs. The communication method is applied to the aforementioned distributed base stations, and fault handling, including processing operations such as fault detection (or troubleshooting), fault isolation, and fault recovery, is performed on the relevant BBUs based on the clock offset between the clock sources of different BBUs. Since there is no need to manually bring in test devices, operational and maintenance costs can be reduced and fault handling efficiency can be improved.

[0088] In an optional implementation, as shown in Figure 5A, if the BBU is directly connected to the radio frequency device, the radio frequency device may select a clock source provided by one of the multiple BBUs to determine the time information synchronized through the BBU as the time information of the local clock. The radio frequency device may calculate the clock offset between the remaining BBUs and the selected BBU by calculating the clock offset between the time information synchronized through the remaining BBUs and the time information of the local clock.

[0089] The following describes in detail the procedure of the communication method provided by this scheme, using an example in which the first BBU represents the BBU selected by the radio frequency device and providing the clock source, and the second BBU represents any BBU other than the selected BBU among the multiple BBUs. As shown in Figure 6, the communication method mainly includes the following steps.

[0090] S601: The radio frequency device acquires first time information and second time information.

[0091] The first time information is time information synchronized by a radio frequency device from the fronthaul interface corresponding to the first BBU. For example, the first BBU and the radio frequency device exchange relevant synchronization packets via the fronthaul interface in accordance with a synchronization protocol such as the Institute of Electrical and Electronics Engineers (IEEE) 1588 protocol (e.g., 1588v2) or the IEEE 1588 protocol combined with the synchronous Ethernet (SyncE) protocol in order to perform time synchronization. Finally, the radio frequency device may obtain the first time information. For example, the first time information may include a first absolute time precise in seconds and a time phase of less than one second. Optionally, the first time information may be described alternatively as first clock synchronization phase information or by another name. This is not limited to this embodiment of the present application.

[0092] In the IEEE 1588 protocol, the clock source provided by the first BBU may be alternatively described as the first master clock. Correspondingly, the first slave clock corresponding to the first master clock is located in the radio frequency device, and the first time information may be understood as the time information of the first slave clock. The IEEE 1588 protocol may be alternatively referred to as the precision time protocol (PTP). In the PTP protocol combined with the SyncE protocol, the first master clock may be alternatively described as the first SyncE+PTP master clock, and the first slave clock may be alternatively described as the first SyncE+PTP slave clock.

[0093] Similarly, the second time information is time information synchronized by a radio frequency device from the fronthaul interface corresponding to the second BBU. For example, the second BBU and the radio frequency device exchange relevant synchronization packets via the fronthaul interface in accordance with the IEEE 1588 protocol (such as 1588v2) or the IEEE 1588 protocol combined with the synchronous Ethernet SyncE protocol in order to perform time synchronization. Finally, the radio frequency device may obtain the second time information. For example, the second time information may include a second absolute time precise to the second and a time phase of less than one second. Optionally, the second time information may be described alternatively as second clock synchronization phase information or by another name. This is not limited to this embodiment of the present application.

[0094] In the IEEE 1588 protocol, the clock source provided by the second BBU may be alternatively described as the second master clock. Correspondingly, the second slave clock corresponding to the second master clock is located in the radio frequency device, and the second time information may be understood as the time information of the second slave clock. The IEEE 1588 protocol may be alternatively referred to as the precision time protocol (PTP). In the PTP protocol combined with the SyncE protocol, the second master clock may be alternatively described as the second SyncE+PTP master clock, and the second slave clock may be alternatively described as the second SyncE+PTP slave clock.

[0095] Optionally, the first BBU is time-synchronized with a first external clock reference source, specifically, the clock source provided by the first BBU (referred to as the first master clock) is synchronized with the first external clock reference source. The second BBU is time-synchronized with a second external reference source, specifically, the clock source provided by the second BBU (referred to as the second master clock) is synchronized with the second external clock reference source. The first and second external clock reference sources may be the same or different. For example, the external clock reference source in this embodiment of the present application may be a global navigation satellite system (GNSS) clock or a 1588V2PTP clock.

[0096] The term "radio frequency device" in this embodiment of the application represents a general concept. For example, if there are multiple radio frequency devices accessing the same fronthaul network, the radio frequency device described in this embodiment of the application may be any one of those multiple radio frequency devices.

[0097] S602: The radio frequency device determines that the first BBU is the master clock device based on the first time information and the second time information.

[0098] Optionally, a radio frequency device may select one time information from time information separately synchronized via multiple BBUs as the time information for the radio frequency device's local clock, according to a best master clock algorithm (BMCA). The BBU corresponding to the selected time information may be referred to as the master clock device or the primary BBU. Alternatively, the local clock of a radio frequency device may be described as the system clock of the radio frequency device or by another name. This is not limited to this embodiment of the present application.

[0099] For example, in accordance with the solution described in S601, if a radio frequency device uses first time information synchronized via a first BBU as the time information for its local clock, according to the BMCA algorithm, the radio frequency device may determine the first BBU as the master clock device. Optionally, if the radio frequency device performs time synchronization with the first BBU according to the IEEE 1588 protocol, it can also be understood that the radio frequency device may determine the first slave clock as the local clock for its radio frequency device, according to the BMCA algorithm.

[0100] Furthermore, optionally, the first BBU may be configured as a master clock device in a predetermined manner. In this case, the radio frequency device may not need to perform S602. In other words, S602 is an optional step, and S602 is indicated by a dashed line in Figure 6.

[0101] S603: The radio frequency device transmits clock offset information to the second BBU.

[0102] The clock offset information indicates the offset between the first time information and the second time information. Optionally, corresponding to the description in S601, the offset between the first time information and the second time information may include two parts: an offset between the first absolute time and the second absolute time, and an offset between time phases of less than one second.

[0103] For example, the first absolute time is denoted as t1, the second absolute time as t2, and the offset between the first absolute time and the second absolute time is the difference between t1 and t2. The offset between time phases within one second can be calculated by using a phase discrimination function. For example, the phase discrimination function is implemented as a phase discrimination unit, which is a component, functional circuit, or software component that can distinguish the phase difference between two input signals. The radio frequency device inputs the time phases within one second contained in the first time information and the time phases within one second contained in the second time information to the phase discrimination unit, and the output of the phase discrimination unit is the offset between the time phases within one second contained in the first time information and the time phases within one second contained in the second time information.

[0104] Corresponding to the fact that a radio frequency device selects a first BBU as the primary BBU and a second BBU is a non-primary BBU, and the first time information synchronized via the first BBU is used as the time information of the radio frequency device's local clock, the clock offset information can also be understood as the offset between the time information synchronized via the non-primary BBU and the time information of the local clock, or as a clock offset between the non-primary BBU and the radio frequency device.

[0105] Correspondingly, the reception of clock offset information from the radio frequency device by the second BBU can be alternatively described as the second BBU receiving clock offset information from the radio frequency device.

[0106] In this application, "transmitting information (e.g., clock offset information) to a device (e.g., a second BBU)" may be understood as the destination of the information being the device. "Transmitting information (e.g., clock offset information) to a device (e.g., a second BBU)" may include directly or indirectly transmitting information to the device. Necessary processing, such as format conversion or frequency conversion, may be performed on the information between the source and destination ends of the information transmission, but the destination end may understand valid information from the source end. Similar descriptions in this application may be understood similarly, and further details are not provided here.

[0107] In this application, "receiving information from a device (e.g., a first radio frequency device)" or "receiving information from a device (e.g., a first radio frequency device)" may be understood as the source end of the information being a device. "Receiving information from a device (e.g., a first radio frequency device)" or "receiving information from a device (e.g., a first radio frequency device)" may include receiving information directly or indirectly from a device. Necessary processing, such as formatting or frequency conversion, may be performed on the information between the source and destination ends of the information transmission, but the destination end may understand valid information from the source end. Similar descriptions in this application may be understood similarly, and further details are not provided here.

[0108] S604: The second BBU determines whether a failure exists in the second BBU based on the clock offset information.

[0109] For example, if the clock offset information is greater than a preset clock offset information threshold, the second BBU may determine that a failure exists in the second BBU. In this case, the second BBU may use a fault isolation method, such as disconnecting from the radio frequency device, to avoid interference between the second BBU and the radio frequency device with other device communications, such as communications between the radio frequency device and the first BBU, caused by the communication between the second BBU and the radio frequency device. The second BBU may also report an anomaly to the administrator or system, and corresponding fault handling, such as troubleshooting, fault isolation, and fault recovery, may be performed manually or automatically by the system. When the second BBU recovers from a failure, it may re-establish a connection to the radio frequency device in order to access it.

[0110] In another example, if the clock offset information is below a pre-set clock offset information threshold, the second BBU may determine that there is no failure in the second BBU and does not need to perform any abnormality reporting.

[0111] In addition, optionally, the radio frequency device may alternatively transmit clock offset information to a network management device, for example, a network management device corresponding to a backhaul interface, for example, the network management device shown in Figure 5A. In this embodiment of the application, there may be two or more BBUs connected to the same radio frequency device. As described above, the second BBU is any of the remaining BBUs in a plurality of BBUs other than the master clock device (first BBU), and the network management device receives clock offset information between each of the remaining BBUs and the master clock device, or alternatively, the network management device may receive clock offset information corresponding to each of the remaining BBUs. Where possible, the clock offset information corresponding to most of the remaining BBUs (e.g., more than a specified percentage) is greater than a preset clock offset information threshold. In this case, the network management device may further determine whether the first BBU is faulty and perform corresponding fault handling.

[0112] For the first BBU used as the master clock device, the radio frequency device may not report clock offset information. Alternatively, and optionally, the radio frequency device may further perform S605 as shown in Figure 6.

[0113] S605: The radio frequency device transmits the first information to the first BBU.

[0114] The first piece of information may indicate one or more of the following: that the first BBU is a master clock device, and that the clock offset between the first BBU and the master clock device is zero. Based on the first piece of information, the first BBU may determine that it is a master clock device.

[0115] In the aforementioned scheme provided in this embodiment of the present application, the radio frequency device can automatically acquire the clock offset between the non-primary BBU and the radio frequency device. This helps to quickly implement measures such as fault isolation and avoid service anomalies caused by clock desync between the BBU and the radio frequency device. Furthermore, it eliminates the need for manual operation and additional test equipment, reducing operational and maintenance costs and improving fault handling efficiency.

[0116] In another optional embodiment, when a BBU is indirectly connected to a radio frequency device by using a switch device in the fronthaul network, the switch device (e.g., the switch device in Figure 5B or switch device 3 in Figure 5C) may select time information from a clock source provided by one of the multiple BBUs, for example, determining the time information synchronized through the BBU as the time information of the switch device's local clock. The switch device may calculate the clock offset between the remaining BBUs and the selected BBU by calculating the clock offset between the time information synchronized through the remaining BBUs and the time information of the local clock.

[0117] The following describes in detail the procedure of the communication method provided by this scheme, using an example in which the first BBU represents the BBU selected by the switch device and providing the clock source, and the second BBU represents any BBU other than the selected BBU among the multiple BBUs. As shown in Figure 7, the communication method mainly includes the following steps.

[0118] S701: A switch device in the fronthaul network acquires first time information and second time information.

[0119] The first time information is time information synchronized by the switch device from the fronthaul interface corresponding to the first BBU. For example, the first BBU and the switch device exchange relevant synchronization packets via the fronthaul interface according to the IEEE 1588 protocol (such as 1588v2) or the IEEE 1588 protocol combined with the SyncE protocol in order to perform time synchronization. Finally, the switch device may obtain the first time information. For example, the first time information may include a first absolute time precise in seconds and a time phase of less than one second. Optionally, the first time information may be described alternatively as first clock synchronization phase information or by another name. This is not limited to this embodiment of the present application.

[0120] In the IEEE 1588 protocol, the clock source provided by the first BBU may be alternatively described as the first master clock. Correspondingly, the first slave clock corresponding to the first master clock may be located in the switch device, and the first time information may be understood as the time information of the first slave clock. The IEEE 1588 protocol may be alternatively referred to as the precision time protocol (PTP). In the PTP protocol combined with the SyncE protocol, the first master clock may be alternatively described as the first SyncE+PTP master clock, and the first slave clock may be alternatively described as the first SyncE+PTP slave clock.

[0121] Similarly, the second time information is time information synchronized by the switch device from the fronthaul interface corresponding to the second BBU. For example, the second BBU and the switch device exchange relevant synchronization packets via the fronthaul interface according to the IEEE 1588 protocol (such as 1588v2) or the IEEE 1588 protocol combined with the Synchronized Ethernet SyncE protocol in order to perform time synchronization. Finally, the switch device may obtain the second time information. For example, the second time information may include a second absolute time precise to the second and a time phase of less than one second. Optionally, the second time information may be described alternatively as second clock synchronization phase information or by another name. This is not limited to this embodiment of the present application.

[0122] In the IEEE 1588 protocol, the clock source provided by the second BBU may be alternatively described as the second master clock. Correspondingly, the second slave clock corresponding to the second master clock may be located in the switch device, and the second time information may be understood as the time information of the second slave clock. The IEEE 1588 protocol may be alternatively referred to as the precision time protocol (PTP). In the PTP protocol combined with the SyncE protocol, the second master clock may be alternatively described as the second SyncE+PTP master clock, and the second slave clock may be alternatively described as the second SyncE+PTP slave clock.

[0123] Optionally, the first BBU is time-synchronized with a first external clock reference source, specifically, the clock source provided by the first BBU (referred to as the first master clock) is synchronized with the first external clock reference source. The second BBU is time-synchronized with a second external reference source, specifically, the clock source provided by the second BBU (referred to as the second master clock) is synchronized with the second external clock reference source. The first and second external clock reference sources may be the same or different. For example, the external clock reference source in this embodiment of the present application may be a GNSS clock or a 1588V2PTP clock.

[0124] S702: The switch device determines that the first BBU is the master clock device based on the first time information and the second time information.

[0125] Optionally, a switch device may, according to the BMCA algorithm, select one time information from time information separately synchronized via multiple BBUs to be used as the time information for the switch device's local clock. The BBU corresponding to the selected time information may be referred to as the master clock device or the primary BBU.

[0126] For example, in correspondence with the solution described in S701, when a switch device uses first time information synchronized via a first BBU as time information for the switch device's local clock in accordance with BMCA, the switch device may determine the first BBU as the master clock device. Optionally, when the switch device performs time synchronization with the first BBU in accordance with the IEEE 1588 protocol, it may also be understood that the switch device determines the first slave clock as the switch device's local clock in accordance with BMCA. Optionally, the switch device's local clock may be alternatively described as the switch device's system clock or by another name. This is not limited to this embodiment of the present application.

[0127] Furthermore, optionally, the first BBU may be configured as a master clock device in a predetermined manner. In this case, the switch device may not need to perform S702. In other words, S702 is an optional step, and S702 is indicated by a dashed line in Figure 7.

[0128] S703: The switch device provides a clock source to the radio frequency device based on first time information.

[0129] The radio frequency device communicates with the first BBU and the second BBU.

[0130] Corresponding to the description in S702, when a switch device uses first time information as time information for the switch device's local clock in accordance with BMCA, the switch device may provide a clock source to the radio frequency device based on the first time information in order to perform synchronization between the radio frequency device and the first BBU. For example, the switch device and the radio frequency device exchange relevant synchronization packets via the fronthaul interface in accordance with a synchronization protocol such as the IEEE 1588 protocol (e.g., 1588v2) or the IEEE 1588 protocol combined with the Synchronized Ethernet SyncE protocol in order to perform time synchronization. Finally, the radio frequency device may obtain third time information synchronized via the switch device. For example, the third time information may include a third absolute time precise in seconds and a time phase of less than one second. Optionally, the third time information may be described alternatively as third clock synchronization phase information or by another name. This is not limited to this embodiment of the present application.

[0131] In the IEEE 1588 protocol, for radio frequency devices, the local clock of a switch device may be considered a master clock that provides a clock source to the radio frequency device. For distinction, in this embodiment of the present application, the master clock that provides a clock source to the radio frequency device is referred to below as a third master clock.

[0132] A third slave clock corresponding to a third master clock may be located in a radio frequency device, and the third time information may be understood as the time information of the third slave clock. The IEEE 1588 protocol may alternatively be referred to as the precision time protocol (PTP). In the PTP protocol combined with the SyncE protocol, the third master clock may alternatively be described as a third SyncE+PTP master clock, and the third slave clock may alternatively be described as a third SyncE+PTP slave clock.

[0133] S704: The switch device transmits clock offset information to the second BBU.

[0134] For details on how to perform this step, please refer to S603. Further details are not described in this embodiment of the present application.

[0135] Furthermore, optionally, the switch device may alternatively transmit clock offset information to a network management device. The network management device may be a network management device corresponding to a backhaul interface, e.g., network management device 1 in Figures 5B / 5C, or the network management device may be a network management device corresponding to a fronthaul network, e.g., network management device 2 in Figures 5B / 5C. In this embodiment of the application, there may be two or more BBUs connected to the same radio frequency device. As described above, the second BBU is any of the remaining BBUs in the plurality of BBUs other than the master clock device (first BBU), and the network management device receives clock offset information between each of the remaining BBUs and the master clock device, or alternatively, the network management device may receive clock offset information corresponding to each of the remaining BBUs. Where possible, the clock offset information corresponding to most of the remaining BBUs (e.g., more than a specified percentage) is greater than a preset clock offset information threshold. In this case, the network management device may further determine whether the first BBU is faulty and perform corresponding fault handling.

[0136] S705: The second BBU determines whether a failure exists in the second BBU based on the clock offset information.

[0137] For details on how to perform this step, please refer to S604. Further details are not described in this embodiment of the present application.

[0138] The switch device may not report clock offset information to the first BBU used as the master clock device. Alternatively, the switch device may optionally perform S706 further, as shown in Figure 7.

[0139] S706: The switch device transmits the first information to the first BBU.

[0140] For details on how to perform this step, please refer to S605. Further details are not described in this embodiment of the present application.

[0141] The aforementioned scheme provided in this embodiment of the present application can automatically monitor synchronization anomalies between multiple BBUs and radio frequency devices and is applicable to fronthaul networking scenarios, enabling rapid implementation of measures such as fault isolation to avoid service anomalies caused by clock asynchronous operation. Furthermore, it eliminates the need for manual operation and additional test equipment, reducing operational and maintenance costs and improving fault handling efficiency.

[0142] It can be understood that the communication method provided in this embodiment of the present application may be further used for fault handling corresponding to a front-haul interface in another scenario, for example, for fault handling of a distributed unit (DU) on a front-haul interface between a DU and a radio unit (RU) in an O-RAN system.

[0143] Based on the same idea, please refer to Figure 8. Embodiments of this application provide a communication device 800. The communication device 800 includes a processing module 801 and a communication module 802. The communication device 800 may be a BBU, an apparatus applied to a BBU, or an apparatus used in matching with a BBU and capable of implementing methods performed on the BBU side. Alternatively, the communication device 800 may be a switch device, an apparatus applied to a switch device, or an apparatus used in matching with a switch device and capable of implementing methods performed on the switch device side. Alternatively, the communication device 800 may be a radio frequency device, an apparatus applied to a radio frequency device, or an apparatus used in matching with a radio frequency device and capable of implementing methods performed on the radio frequency device side.

[0144] The communication module may alternatively be called a transceiver module, transceiver, transceiver device, or transceiver apparatus. The processing module may alternatively be called a processor, processing board, processing unit, or processing unit. Optionally, the processing module may control the communication module to perform the transmit and receive operations of the BBU, switch device, or radio frequency device in the manner described above.

[0145] It should be noted that communication modules and / or processing modules may be implemented using virtual modules. For example, a processing module may be implemented using a software function unit or virtual device, and a communication module may be implemented using a software function or virtual device. Alternatively, processing modules and / or communication modules may be implemented using entity devices. For example, if the device is implemented using a chip / chip circuit, the communication module may be an input / output circuit and / or a communication interface, performing input operations (corresponding to the receiving operations described above) and output operations (corresponding to the transmitting operations described above). A processing module may be an integrated processor, microprocessor, or integrated circuit.

[0146] The modularization in this embodiment of the present application is merely an example, and is simply a modularization into logical functions; other modularizations may be used in actual implementations. In addition, the functional modules in the examples of the embodiments of the present application may be integrated into a single processor, and each functional module may exist physically independently, or two or more functional modules may be integrated into a single module. The integrated module may be implemented in hardware form or in the form of a software functional module.

[0147] In this embodiment of the present application, the functions of the processing module and / or communication module within the BBU, switch device, or radio frequency device are further subdivided.

[0148] A communication module in the first or second BBU (shown by using eCPRI as an example in Figure 9A or Figure 9B) corresponds to a fronthaul interface and is configured to exchange synchronous packets corresponding to the IEEE 1588 protocol and the SYNCE protocol with a switch device or radio frequency device. The eCPRI in the first BBU transmits synchronous packets provided by the first SyncE+PTP master clock and receives packets fed back from the fronthaul interface by the first SyncE+PTP slave clock. The eCPRI in the second BBU transmits synchronous packets provided by the second SyncE+PTP master clock and receives packets fed back from the fronthaul interface by the second SyncE+PTP slave clock.

[0149] A processing module within the first or second BBU includes a time synchronization performance monitoring unit. Corresponding to the embodiments described above, the eCPRI within the second BBU is further configured to receive clock offset information transmitted by a switch device or radio frequency device and to transmit the clock offset information to the time synchronization performance monitoring unit. The time synchronization performance monitoring unit is configured to perform fault handling on the second BBU based on the clock offset information. It can be understood that the time synchronization performance monitoring unit may alternatively be located in another device, for example, a network management device corresponding to a fronthaul network or a network management device corresponding to a backhaul interface. Further details are not described in this embodiment of the present application.

[0150] Figure 9A shows the internal structure of the first BBU, the second BBU, and the radio frequency device in the solution described in Figure 6. The first BBU, the second BBU, and the radio frequency device exchange synchronization packets corresponding to the IEEE 1588 protocol and the SyncE protocol. The communication module within the radio frequency device includes a first communication interface that communicates with the first BBU and a second communication interface that communicates with the second BBU. The second communication interface exchanges synchronization packets corresponding to the IEEE 1588 protocol and the SyncE protocol with the radio frequency device. The first communication interface is implemented by using a first eCPRI. The first eCPRI within the radio frequency device forwards the received synchronization packets to a first SyncE+PTP slave clock, and outputs the packets, which have been fed back by the first SyncE+PTP slave clock, to the fronthaul interface. After interaction and synchronization according to the IEEE 1588 protocol and the SyncE protocol, the first SyncE+PTP slave clock outputs first time information. The second communication interface is implemented by using a second eCPRI. The second eCPRI within the radio frequency device forwards received synchronization packets to a second SyncE+PTP slave clock, and outputs the packets, which have been fed back by the second SyncE+PTP slave clock, to the fronthaul interface. After interaction and synchronization according to the IEEE1588 protocol and the SyncE protocol, the second SyncE+PTP slave clock outputs second time information.

[0151] The processing module within the radio frequency device includes a BCMA source selection unit and a clock offset calculation unit. The BCMA source selection unit is configured to select one of the first SyncE+PTP slave clock and the second SyncE+PTP slave clock as the local clock. Figure 9A shows the BCMA source selection unit selecting the first SyncE+PTP slave clock as the local clock.

[0152] Furthermore, the local clock time information (i.e., the first time information) is used as one input to the clock offset calculation unit, and the second time information is used as another input to the clock offset calculation unit. The clock offset calculation unit can directly calculate the offset between the first absolute time contained in the first time information and the second absolute time contained in the second time information. In addition, the clock offset calculation unit uses a phase identifier to determine the offset between a time phase of less than one second contained in the first time information and a time phase of less than one second contained in the second time information. The second eCPRI of the radio frequency device reports the clock offset information, i.e., the offset between the first time information and the second time information, to the second BBU.

[0153] Figure 9B shows the internal structure of the first BBU, second BBU, switch device, and radio frequency device in the solution described in Figure 7. The first BBU, second BBU, and switch device exchange synchronous packets corresponding to the IEEE 1588 protocol and the SyncE protocol. The communication module within the switch device includes a first communication interface (or referred to as the first transmission interface) that communicates with the first BBU and a second communication interface (or referred to as the second transmission interface) that communicates with the second BBU. The second communication interface exchanges synchronous packets corresponding to the IEEE 1588 protocol and the SyncE protocol with the radio frequency device. The first communication interface within the switch device forwards the received synchronous packets to the first SyncE+PTP slave clock, and the packets fed back by the first SyncE+PTP slave clock are sent to the eCPRI of the first BBU. After interaction and synchronization according to the IEEE1588 protocol and the SyncE protocol, the first SyncE+PTP slave clock outputs first time information. The second communication interface in the switch device forwards the received synchronization packet to the second SyncE+PTP slave clock, and the packet, fed back by the second SyncE+PTP slave clock, is sent to the eCPRI of the second BBU. After interaction and synchronization according to the IEEE1588 protocol and the SyncE protocol, the second SyncE+PTP slave clock outputs second time information.

[0154] The processing module within the switch device includes a BCMA source selection unit and a clock offset calculation unit. The BCMA source selection unit is configured to select one of the first SyncE+PTP slave clock and the second SyncE+PTP slave clock as the system clock. Figure 9B shows the BCMA source selection unit selecting the first SyncE+PTP slave clock as the system clock.

[0155] Furthermore, the time information of the system clock (i.e., the first time information) is used as one input to the clock offset calculation unit, and the second time information is used as another input to the clock offset calculation unit. The clock offset calculation unit can directly calculate the offset between the first absolute time contained in the first time information and the second absolute time contained in the second time information. In addition, the clock offset calculation unit uses a phase identifier to determine the offset between a time phase of less than one second contained in the first time information and a time phase of less than one second contained in the second time information. The second communication interface of the switch device reports the clock offset information, i.e., the offset between the first time information and the second time information, to the second BBU.

[0156] Furthermore, the communication module of the switch device may further include a third communication interface. After the switch device determines the system clock, the system clock may be used as a third SyncE+PTP master clock corresponding to the radio frequency device. The third communication interface exchanges synchronization packets with the radio frequency device in accordance with the IEEE 1588 protocol and the SyncE protocol. The communication module in the radio frequency device (implemented, for example, using eCPRI) forwards the received synchronization packets to the third SyncE+PTP slave clock and transmits the packets, fed back by the third SyncE+PTP slave clock, to the third communication interface of the switch device. After interaction and synchronization in accordance with the IEEE 1588 protocol and the SyncE protocol, the third SyncE+PTP slave clock in the radio frequency device may output third time information.

[0157] It can be understood that there may be one or more radio frequency devices in Figure 9B. The switching device may select the same or different master clock sources for different radio frequency devices. Figure 9B shows only one radio frequency device as an example.

[0158] Based on the same technical concept, embodiments of the present application further provide a communication device 1000. For example, the communication device 1000 may be a chip or a chip system. Optionally, in this embodiment of the present application, the chip system may include a chip, or it may include a chip and other separate devices.

[0159] The communication device 1000 may include at least one processor 1010. Optionally, the processor 1010 is coupled to memory. The memory may be located within the device. Alternatively, the memory may be integrated with the processor. Alternatively, the memory may be located outside the device. For example, the communication device 1000 may further include at least one memory 1020.

[0160] The processor 1010 may be a general-purpose processor, a digital signal processor, an application-specific integrated circuit, a field-programmable gate array or another programmable logic device, a separate gate or transistor logic device, or a separate hardware component that can implement or perform the methods, steps, and logic block diagrams disclosed in embodiments of this application. The general-purpose processor may be a microprocessor or any conventional processor, etc. For example, the processor 1010 may be a baseband processor or a central processing unit. The baseband processor may be configured to process communication protocols and communication data. The central processing unit may be configured to control communication equipment (e.g., radio frequency control devices, radio frequency devices, RAN nodes, terminals, or chips), execute software programs, and process data from software programs.

[0161] The communication device 1000 is applied to the aforementioned radio frequency device. In the design, the processor 1010 may include a program 113 (which may alternatively be called code or instructions). The program 113 may run on the processor 1010 and cause the communication device 1000 to perform the method on the radio frequency device side in the aforementioned embodiment. In another possible design, the communication device 1000 includes circuitry (not shown in Figure 10) configured to implement the function on the radio frequency device side in the aforementioned embodiment. Optionally, the processor 1010 may further store data.

[0162] The communication device 1000 is applied to the aforementioned switch device. In the design, the processor 1010 may include a program 113 (which may alternatively be called code or instructions). The program 113 is executed on the processor 1010 and may cause the communication device 1000 to perform the method on the switch device side in the aforementioned embodiment. In another possible design, the communication device 1000 includes circuitry (not shown in Figure 10) configured to implement the function on the switch device side in the aforementioned embodiment. Optionally, the processor 1010 may further store data.

[0163] The communication device 1000 is applied to a BBU (e.g., a first BBU or a second BBU). In the design, the processor 1010 may include a program 113 (which may alternatively be called code or instructions) which is executed on the processor 1010, causing the communication device 1000 to perform the method on the BBU side in the embodiments described above. In another possible design, the communication device 1000 includes circuitry (not shown in Figure 10) which is configured to implement the function on the BBU side in the embodiments described above. Optionally, the processor 1010 may further store data.

[0164] Memory 1020 may be non-volatile memory, such as a hard disk drive (HDD) or solid-state drive (SSD), or volatile memory, such as random access memory (RAM). Memory is any other medium that can be used to carry or store expected program code in the form of instructions or data structures and that can be accessed by a computer, but is not limited to such other medium. Memory in embodiments of the present application may alternatively be any other device that can implement circuitry or storage functions and is configured to store programs and / or data. For example, memory 1020 may store program 114 (which may alternatively be called code or instructions), program 114 may be executed on processor 1010, causing communication device 1000 to perform the method described in the embodiments of the above method.

[0165] Optionally, the processor 1010 may further include an artificial intelligence (AI) module 1110, and / or the memory 1020 may further include an AI module 118. The AI ​​module is configured to implement AI-related functions. The AI ​​module may be implemented using software, hardware, or a combination of software and hardware. For example, the AI ​​module may include a radio access network intelligent controller (RAN intelligent controller, RIC) module. For example, the AI ​​module may be a near real-time RIC or a non-real-time RIC.

[0166] The communication device 1000 may further include a transceiver 1030 and / or an antenna 1040. Alternatively, the transceiver 1030 may be called a transceiver unit, transceiver machine, transceiver circuit, transceiver, etc., and is configured to implement the transceiver function of the communication device. For example, the transceiver 1030 may be a transceiver machine, circuit, bus, module, pin, or another type of communication interface. If the communication device 1000 is a chip-type device or circuit, the transceiver 1030 within the communication device 1000 may alternatively be an input / output circuit that can input information (or is said to receive information) and can output information (or is said to transmit information). Optionally, if the communication device 1000 includes an antenna 1040, the transceiver 1030 is configured to implement the transceiver function of the communication device by using the antenna 1040.

[0167] The coupling in this embodiment of the present application may be an indirect coupling or communication connection between devices, units, or modules in an electrical, mechanical, or other form, used for information exchange between devices, units, or modules. The processor 1010 may work in cooperation with one or more of the memory 1020, transceiver 1030, and antenna 1040. The specific connecting medium between the processor 1010, memory 1020, transceiver 1030, and / or antenna 1040 is not limited to this embodiment of the present application. For example, the processor 1010, memory 1020, and transceiver 1030 are connected to each other by using a bus. The bus may be a peripheral component interconnect (PCI) bus, an extended industry standard architecture (EISA) bus, or the like. The bus may be classified as an address bus, data bus, control bus, etc.

[0168] Based on the examples described above, embodiments of the present application further provide a communication system comprising at least one BBU and at least one radio frequency device. The communication system may implement the communication method provided in the example shown in Figure 6.

[0169] Embodiments of this application further provide a communication system comprising at least one BBU, a switch device in a fronthaul network, and at least one radio frequency device. The communication system may implement a communication method provided in the example shown in Figure 7.

[0170] The technical solutions provided in this embodiment of the present application may be implemented in whole or in part through software, hardware, firmware, or any combination thereof. When the embodiment is implemented using software, all or part of the embodiment may be implemented in the form of a computer program product. A computer program product includes one or more computer instructions. When the computer program instructions are loaded onto a computer and executed, all or some of the procedures or functions according to the embodiment of the present application are generated. The computer may be a general-purpose computer, a dedicated computer, a computer network, a network management device, or another programmable device. The computer instructions may be stored on a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, computer instructions may be transmitted from a website, computer, server, or data center to another website, computer, server, or data center by wired (e.g., coaxial cable, optical fiber, or digital subscriber line (DSL)) or wireless (e.g., infrared, radio, or microwave). Computer-readable storage media can be any available medium accessible by a computer, or a data storage device such as a server or data center that integrates one or more available media. Available media can be magnetic media (e.g., floppy disks, hard disks, or magnetic tapes), optical media (e.g., digital video discs (DVDs)), semiconductor media, etc.

[0171] In embodiments of this application, examples may be referenced to one another, provided that there is no logical inconsistency. For example, methods and / or terms in embodiments of methods may be referenced to one another, functions and / or terms in embodiments of apparatus may be referenced to one another, and functions and / or terms between examples of apparatus and examples of methods may be referenced to one another.

[0172] It will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments without departing from the scope of the embodiments of this application. Thus, the embodiments of this application are also intended to cover these modifications and variations, provided that they fall within the scope of the claims of the embodiments of this application and the equivalent art.

Claims

1. A communication method performed by a radio frequency device, The acquisition of first time information and second time information, wherein the first time information is time information synchronized via a front-haul interface corresponding to a first baseband unit, and the second time information is time information synchronized via a front-haul interface corresponding to a second baseband unit. Transmitting clock offset information, wherein the clock offset information indicates the offset between the first time information and the second time information. Includes, Transmitting the aforementioned clock offset information means A method characterized by transmitting the clock offset information to the second baseband unit, wherein the clock offset information is used for fault detection of the second baseband unit.

2. Before transmitting the aforementioned clock offset information, The method according to claim 1, further comprising determining that the first baseband unit is a master clock device based on the first time information and the second time information.

3. The method according to claim 1, further comprising providing a clock source to a radio frequency device based on the first time information, wherein the radio frequency device communicates with the first baseband unit and the second baseband unit.

4. Transmitting first information to the first baseband unit, wherein the first information is The first baseband unit is a master clock device, and The clock offset between the first baseband unit and the master clock device is zero. The method according to claim 1, further comprising indicating one or more of the following.

5. The method according to claim 1, characterized in that the first baseband unit is time-synchronized with a first external clock reference source, the second baseband unit is time-synchronized with a second external clock reference source, and the first external clock reference source and the second external clock reference source are the same or different.

6. A communication method performed by a second baseband unit, The method involves receiving clock offset information, wherein the clock offset information indicates an offset between first time information and second time information, the first time information is time information synchronized via a fronthaul interface corresponding to a first baseband unit, and the second time information is time information synchronized via a fronthaul interface corresponding to a second baseband unit. Based on the clock offset information, it is determined whether or not there is a malfunction in the second baseband unit. A method characterized by including the following.

7. The method according to 6, characterized in that the first baseband unit is a master clock device.

8. The method according to 6, characterized in that the first baseband unit is time-synchronized with a first external clock reference source, the second baseband unit is time-synchronized with a second external clock reference source, and the first external clock reference source and the second external clock reference source are the same or different.

9. A communication device configured to carry out the method described in claim 1.

10. A second baseband unit which is a communication device configured to carry out the method described in claim 6.

11. A communication device comprising a processor, wherein the processor is coupled to a memory, and the processor is configured to call computer program instructions stored in the memory to perform the method according to any one of claims 1 to 5.

12. A communication device comprising a processor, wherein the processor is coupled to a memory, and the processor is configured to call computer program instructions stored in the memory to perform the method according to any one of claims 6 to 8.

13. A communication system comprising the communication device described in claim 9 and the second baseband unit described in claim 10.

14. A computer-readable storage medium, wherein the computer-readable storage medium stores instructions, and when the instructions are executed on a computer, the computer is able to perform the method according to any one of claims 1 to 5 or any one of claims 6 to 8.

15. A computer program including instructions, wherein when the instructions are executed on a computer, the computer becomes capable of performing the method according to any one of claims 1 to 5 or the method according to any one of claims 6 to 8.

Images